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  • Open access
  • 19 Reads
GEOLOGICAL RAW MATERIALS FROM A MESOLITHIC ARCHAEOLOGICAL SITE IN NW PORTUGAL

Geological raw materials have been (are and will be) an important resource in the development of human culture. They are a major (sometimes the only) source of information on the habits of humanity earliest periods (Paleolithic and Mesolithic).

The present work concerns the study of geological raw materials obtained from an excavation site located in Serra da Cabreira (NW Portugal). This archaeological site is a shelter established under big granite boulders (resulting from geological processes - weathering and erosion). The majority of the artefacts exhumed from this archaeological site are made in different quartz varieties (with minor flint occurrences of flint). The dominant quartz varieties are grey quartz and milky quartz, which are similar to diverse occurrences of quartz veins found in the immediate neighborhood of the shelter.

Nonetheless, there are diverse other quartz varieties (rose, smoky and hyaline), indicating the possibility of more specific locations that are farther away from the shelter, which could give indications of potential sources. Therefore, it is of major importance the study of the possible relations between quartz varieties and the techno-typology of archaeological artefacts.

In this sense, the study of geological raw materials can be seen as an important source of archaeological information, illustrating the evolution of past relationships between humans and geological resources, which might also become relevant information for the present and for the future, considering namely the extremely low environmental impact of the processing of raw materials.

  • Open access
  • 14 Reads
Nonlinear Dynamics of seismicity and fault zone strain around large dam: the case of Enguri dam, Caucasus.

Monitoring of seismic activity in the area of large dam is a unique tool for understanding the intimate connections between earthquakes generation and man-made regular quasi-periodic strains in the Earth, created by seasonal water load-unload in the reservoir. We can consider large dams’ area as a large natural laboratory, providing possibility of studying seismic process in almost controlled (repeated) conditions. The 271 m high Enguri arc dam was built in the canyon of Enguri river in West Georgia. It is located in a zone of high seismicity (M7.5). The water level high in the lake varies seasonally by 100 m, which means that Enguri reservoir can activate Reservoir-Triggered Seismicity (RTS). Due to a high seismic activity of the region, the seismic station’s network was installed in the area of Enguri dam well before its construction with the aim of studying possible reservoir-triggered activity. The RTS pattern in the Enguri area should depend on the Water Level (WL) variation regime in the lake. The main goal of the paper is to apply new methods of complexity analysis (DFA, RQA and LZC) in order to assess in a quantitative way the correlation between WL variations and local seismicity and assess the impact of man-made activity on the local seismicity pattern.

  • Open access
  • 12 Reads
GEOLOGICAL MATERIALS AS SOURCES OF Rn EMISSIONS

Geological materials are a potential source of pollutants, among which the most widespread in the built environment is the radioactive isotope Rn-222. This isotope is the result of radioactive decay of uranium (U-238). It is emitted as a gas, which allows it to enter the human body, with the potential to affect internal organs (mostly the lungs) by alpha particles production.
While the presence of uranium in the materials is a necessary condition for the production of Rn-222, the amount of gas emitted by the material depends on other characteristics that allow the migration of the gas.
The main aim of this communication concerns the review of emission values from geological materials and their relation to physical and petrographic characteristics to assess the risk associated with them when they are in terrains or when they are used as building materials.

  • Open access
  • 13 Reads
Natural time analysis: Results related to two earthquakes that occurred in Greece during 2019

The following two earthquakes occurred in Greece during 2019: First, a Mw5.4 earthquake [1] close to Preveza city in Western Greece on 5 February and a Mw5.3 earthquake [2] 50km East of Patras on 30 March. Here, we present the natural time analysis [3] of the seismic electric signals (SES) activities [4,5] that have been recorded before these two earthquakes. In addition, we explain how we can identify the occurrence times of these two earthquakes by analyzing in natural time the seismicity subsequent to the SES activities.

References

[1] European Mediterranean Seismological Center, M5.4-GREECE- 2019-02-05 02:26:09UTC https://www.emsc-csem.org/Earthquake/earthquake.php?id=742939

[2] European Mediterranean Seismological Center, M5.3-GREECE-2019-03-30 10:46:18UTC https://www.emsc-csem.org/Earthquake/earthquake.php?id=754693

[3] P. A. Varotsos, N. V. Sarlis and E. S. Skordas, Natural Time Analysis: The new view of time. Precursory Seismic Electric Signals, Earthquakes and other Complex Time-Series, Springer-Verlag, Berlin Heidelberg (2011) 449 pages.

[4] P. Varotsos and K. Alexopoulos, Physical properties of the variations of the electric field of the Earth preceding earthquakes, I. Tectonophysics 110, 73-98, 1984.

[5] P. Varotsos and K. Alexopoulos, Physical properties of the variations of the electric field of the Earth preceding earthquakes, II. Determination of epicenter and magnitude, Tectonophysics 110, 99-125, 1984.

  • Open access
  • 20 Reads
Eocene North American Testudinidae and Geoemydidae (Retilia, Testudines): A re-evaluation of their alpha taxonomy and paleogeography

The alpha taxonomy and paleogeography of testudinid and geoemydid turtles of the early Eocene (Wasatchian-Bridgerian) of western North America have received little attention since their original description. We reassess the alpha taxonomy of six species of the genera Echmatemys and Hadrianus. Additionally, we analyze new material, including juvenile specimens of Hadrianus corsoni, H. majusculus, E. haydeni and E. naomi. Proceeding taxonomic assessment we also examined a large sample of extant Gopherus agassizii to help us understand what characters were and were not consistent between individuals. This led us to use different characters than other recent assessments of fossil testudinoid morphology. A phylogenetic analysis reveals that the four nominal species of Echmatemys examined form a polyphyletic group, with E. lativertabralis as the outlier. In examining the global stratigraphic distribution of early Testudinidae we conclude that the oldest and most basal tortoises are from the western United States. From this we conclude that the Testudinidae likely evolved in North America from one of the geoemydid-like forms lumped in the genus Echmatemys, which have their lowest stratigraphic occurrence in the earliest Wasatchian North American land-mammal “age” (early Eocene, Ypresian). From here we suggest a bi-directional migration of testudinids to Europe and Asia took place. The Asian migration gave rise to the extant Manouria lineage and the European migration spawned all extant tortoises more derived than Manouria and Gopherus.

  • Open access
  • 15 Reads
Multifractal characterization of seismic activity at Esmeraldas and Manabí provinces (Ecuador)

Due to the enormous impact of the seismic activity and the need to deepen more in the detailed knowledge of its behaviour, this research work describe an analysis of the multifractal nature of the magnitude, inter-distance and interevent time series of the earthquakes that occurred at the provinces of Manabí and Esmeraldas in Ecuador, during the years 2011-2017, which is an area with a high seismic activity. For this study the Multifractal Detrended Fluctuation Analysis or (MF-DFA) has been used, which allows the detection of multifractality in non-stationary series as well as a series of parameters of non-linear characterization. The obtained results revealed that the interevent time series presents the higher degree of multifractality than the two previously mentioned. In addition, the Hurst exponent values were in a non-proportional function to (q), which is a weight value indicating the multifractal behaviour of the dynamics of the earthquakes analysed in this work. Finally, several multifractal parameters were calculated resulting that all the series were skewed to the right which reflects that small variations in the series are more dominant than large fluctuations.

  • Open access
  • 14 Reads
CONFORMATION OF THE INTERDISCIPLINARY TEAM "KILLALAB" AS A TOOL FOR ASTROBIOLOGY EXPERIMENTS
Published: 04 June 2019 by MDPI AG in 2nd International Electronic Conference on Geosciences session Others

The development of new technologies in recent years has highlighted interdisciplinarity as a tool to solve complex problems faced by scientists and engineers in research work. Worldwide, the area of ​​space science and specifically astrobiology has more than 25 missions with high technological development and economic return. However, the success of interdisciplinary teams requires collaboration, responsibility, and leadership on the part of all members, to prioritize the main objectives of the research. Likewise, the formation of interdisciplinary teams can be affected because there is little information about the strategies and tools that recognize the opportunities of the constant interaction of subjects from engineering and sciences. We use a methodology based on other recent proposals that include the description of the conformation and behavior of the research team and the measurement of interdisciplinarity through the interrelation and the level of dependence of the existing subject categories in Killalab team. In this research, we present the ensemble interdisciplinary group "Killalab" and its implication in the realization of astrobiological investigations.

  • Open access
  • 8 Reads
APPROACHES TO THE STUDY OF SALT WEATHERING OF GEOLOGICAL MATERIALS

Salt weathering affects diverse geological materials in historical and contemporary structures. Its characterization is important to evaluate the hazard level to the materials and the measures to remediate or at least to mitigate their effects.
The present communication reviews different approaches to the study of salt weathering along two main lines:
- simulation experiences (including exposure experience and laboratory tests) which are based on ad hoc conditions specifically designed for the goal of assessing the impact of salt weathering;
- case studies of real structures based, mostly, in fieldwork, which might be complemented by laboratory analyses of the products of salt weathering and the potential sources of salt contaminants.
Our goal is to discuss the usefulness and limitations of these approaches to the research of the main issues related to this subject such as the migration and concentration of salt pollutants and their relation with the development of decay features affecting building stones applied in fieldwork the built environment.

  • Open access
  • 5 Reads
Top down instead of bottom up chronostratigraphic definitions

Since the 1960s, the Phanerozoic chronostratigraphic scale has been defined/redefined by the method of Global Stratotype Sections and Points (GSSPs). The GSSP method defines stage bases, and, where proximate, equates them to the bases of larger chronostratigraphic units. For example, the GSSP that defines the base of the Fortunian Stage also defines the bases of the Terreneuvian Series, Cambrian System, Paleozoic Erathem and Phanerozoic Eonothem. Indeed, via the GSSP method the term Phanerozoic and its subdivisions above the stage level have no particular significance other than as successively larger “pigeonholes” within which to bin stages. The recognition of a single set of global stages is also one of the cornerstones of the GSSP method, though no stage can be correlated globally because of facies changes, taphonomic biases and/or provincialism. Thus, the concept of global standard stages is an unworkable abstraction that should be abandoned. The bottom-up hierarchical reductionism of the GSSP method has reduced the information of chronostratigraphic classification. Series, systems, erathems and eonothems are conceptually more than just collections of stages. Their bases are marked by significant natural events such as the Cambrian explosion, the end-Permian mass extinction in the ocean, etc., that should play a role in chronostratigraphic definition. The GSSP method thus embodies a reductionism that trivializes the boundaries of chronostratigraphic boundaries larger than stages. Stratigraphers should return to a top down chronostratigraphy that defines chronostratigraphic units larger than stages by significant natural events of global correlateability.

  • Open access
  • 15 Reads
SAMA-VTOL Aerial Image Dataset (SVAID): A New UAV Image Dataset for Advanced Remote Sensing Research

SAMA-VTOL aerial image dataset (SVAID) is a new open unmanned aerial vehicles (UAV) image dataset for a wide range of scientific projects in remote sensing (i.e. 3D object modeling, rural/urban mapping, digital elevation/surface model processing, etc.). Open high-quality UAV images play an important part in providing and expanding spatial data processing methods. The SVAID includes 120 rural/urban scene images with 80% overlap between images (forward overlap) and 60% overlap between flight lines (side overlap) from part of Esfahan province, Iran. The characteristics that make the SVAID an excellent scientific dataset are: (i) very high ground sampling distance (GSD) due to suitable fly height selection; (ii) GNSS-PPK (Post Processing Kinematic) system for improving the spatial accuracy without ground control points (GCPs); (iii) various landscape types (i.e. different types of roofs for commercial/residential buildings, vegetation, etc.), and (iv) uses of the new UAV-photogrammetry platform, named SAMA-VTOL (2019) has been developed by TAREQH Corporation. Additionally, The Agisoft Metashape software was used to analyzing images and produce point clouds, digital surface model (DSM) and orthoimage for evaluating SVAID quality and quantity.

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